Development of nasal and throat spray based on Värska mineral water from Gdov aquifer, Estonia

The Värska 6 well extracts mineral water from the sandstones of the Gdov aquifer at a depth of 575–595 m, with a total dissolved solids contents varying between 17 and 27 g/L. The aim of the work was to study 1) the market for nasal/throat sprays in Estonia; 2) the opinions of pharmacy employees and customers; 3) the composition and sterility of the mineral water; and 4) the possibility of developing a nasal/throat spray based on local mineral water. A total of 17 nasal sprays were marketed in Estonia in 2022, of which 12 were for nasal use only and 5 were nasal/throat sprays. Most (70%) were solutions with isotonic salt concentrations made from dissolved or undiluted sterilised seawater or ocean water. The indications for their use are diverse, ranging from daily nasal hygiene to the relief of colds. Värska 6 water has a high salinity (20 g/L), a Na–Cl chemical type, and – compared to ocean water and nasal sprays made from ocean water – is enriched in lithophile elements (Fe, Mn, Li, Sr, and Ba) characteristic of deep groundwater. The hypertonic Värska 6 mineral water is bacteriologically clean, and the temporal stability test confirmed that the mineral water does not promote bacterial growth but inhibits it. A new product was developed – the mineral water-based hypertonic nasal/throat spray Tsilk.